It is a recent trend to obtain a folding-type portable telephone in a market of portable telephones. In particular, a folding-type portable telephone rendered to be thin is required in the market. Therefore, folding-type portable telephones each aiming at a thin-type appears in the market one by one (For example, Patent references 1, 2 should be referred). However, it is always an object for realizing the thin-type to achieve strength of the folding-type portable telephone.    Patent reference 1: An official gazette of an unexamined Japanese patent publication 2004-251938    Patent reference 2: An official gazette of an unexamined Japanese patent publication 2005-039670